title: Utility of cardiac biomarkers for the diagnosis of type V myocardial infarction after coronary artery bypass grafting: insights from serial cardiac MRI.
abstract: OBJECTIVE
  To examine, using cardiac magnetic resonance (CMR), the utility of cardiac biomarkers for the determination of myocyte necrosis and function after coronary artery bypass grafting (CABG), and to test the recently updated guidelines for the diagnosis of postoperative myocardial infarction (type V MI).
  
  
  RESULTS
  Forty patients included in a single-centre randomised trial of two surgical techniques for performing CABG underwent serial assessment with CMR biochemical markers. Cine and delayed enhancement CMR (DE-CMR) for assessment of left ventricular (LV) function and irreversible myocyte necrosis was performed and levels of troponin I (TnI) and creatine kinase-MB isoform (CK-MB) were determined. The area under the curve for TnI strongly correlated with the mass of new myocyte necrosis as assessed by DE-CMR (r = 0.83, p<0.001), compared with CK-MB (r=0.39, p=0.06). Furthermore, routine assessment of TnI alone at 24 h (> 6.6 μg/l) predicted type V MI on DE-CMR with a sensitivity of 88% and specificity of 97%, whereas CK-MB predicted type V MI with a sensitivity of 75% and specificity of 87%.
  
  
  CONCLUSIONS
  Biomarkers alone (TnI), at an appropriate threshold appear robust for the detection of type V MI, independently of supplementary evidence, as suggested by the ESC/ACCF/AHA/WHF criteria. Clinical trial registration information The study is listed on the Current Controlled Trials Registry: ISRCTN41388968. URL: http://www.controlled-trials.com.
authors.affiliation: Department of Cardiovascular Medicine, Flinders University, Flinders Drive, Flinders Medical Centre, Bedford Park SA 5042, Australia.
authors.forename: Tammy J
authors.initials: TJ
authors.lastname: Pegg
authors.forename: Zoe
authors.initials: Z
authors.lastname: Maunsell
authors.forename: Theodoros D
authors.initials: TD
authors.lastname: Karamitsos
authors.forename: Richard P
authors.initials: RP
authors.lastname: Taylor
authors.forename: Tim
authors.initials: T
authors.lastname: James
authors.forename: Jane M
authors.initials: JM
authors.lastname: Francis
authors.forename: David P
authors.initials: DP
authors.lastname: Taggart
authors.forename: Harvey
authors.initials: H
authors.lastname: White
authors.forename: Stefan
authors.initials: S
authors.lastname: Neubauer
authors.forename: Joseph B
authors.initials: JB
authors.lastname: Selvanayagam
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000378:metabolism; D001026:Coronary Artery Bypass; D052279:Creatine Kinase, MB Form / Q000378:metabolism*; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis*; D032383:Myocytes, Cardiac / Q000473:pathology*; D009336:Necrosis; D011183:Postoperative Complications / Q000175:diagnosis*; D011446:Prospective Studies; D019210:Troponin I / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D019210:Troponin I; D052279:Creatine Kinase, MB Form